Sensing Circuit Noise Compensation for Display Luminance
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Solution Overview
Problem
Flat panel display devices face luminance deviations due to variations in driving characteristics between pixels, which are difficult to compensate accurately due to noise distortion in sensing data from existing sensing circuits.
Innovation Solution
A sensing circuit design that includes a first line selection switch, a noise selection switch, a second line selection switch, and a second noise selection switch, allowing for alternating sampling periods to isolate and offset noise from sensing lines, enabling accurate compensation of pixel driving characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a sensing circuit samples sensing voltage from sensing lines to measure pixel driving characteristics, then measurement capability is improved, but noise is simultaneously sensed causing data distortion
Solution Approach 1:
The sensing operation is segmented into distinct time periods: a first sensing period where sensing voltage is sampled, and a second sensing period where noise is sampled. This temporal segmentation allows separate measurement of the desired signal and the interference, enabling subsequent noise subtraction to achieve accurate sensing data without distortion
Solution Approach 2:
Noise is sampled in advance during the second sensing period before the final sensing data is calculated. By preliminarily capturing the noise characteristics on the sensing lines, the system can later subtract this noise from the sensing voltage measurement, eliminating data distortion and achieving precise measurement
2Adaptability or versatility
If sensing lines are used to sense pixel driving characteristics, then sensing coverage is improved, but noise interference on sensing lines increases
Solution Approach 1:
The noise present on the sensing lines during sensing operations is converted from a harmful factor into a useful measurement target. By intentionally sampling the noise on the sensing lines during a dedicated second sensing period, the system obtains accurate noise characteristics that can be subtracted from the sensing voltage, transforming the interference into a benefit for achieving noise-free sensing data
Solution Approach 2:
The sensing circuit employs periodic alternating operations between two sensing periods: one for sampling sensing voltage and another for sampling noise on the sensing lines. This periodic action allows systematic separation of signal and noise measurements, enabling the system to maintain broad sensing coverage while eliminating noise interference through temporal multiplexing
Data Source
AI summary
A sensing circuit includes a first line selection switch which connects a first sensing line to a sensing channel in a first sub-sensing period, a first noise selection switch which connects the first sensing line to a reference channel in a second sub-sensing period, a second line selection switch which connects a second sensing line to the sensing channel in the second sub-sensing period, and a second noise selection switch which connects the second sensing line to the reference channel in the first sub-sensing period. The sensing channel samples a first sensing voltage and noise of the first sensing line and the reference channel samples noise of the second sensing line in a first sampling period, and the sensing channel samples a second sensing voltage and noise of the second sensing line and the reference channel samples noise of the first sensing line in a second sampling period.